(a) Field of the Invention
The present invention concerns devices for smelting metals with rotary furnaces, and more particularly a process for utilizing at least a smelting line including at least one rotary furnace with oxy-combustible burner, and comprising the steps of loading the furnaces with pieces of metal to be molten, smelting the metal and casting the molten metal.
(b) Description of Prior Art
Rotary furnaces with oxy-combustible burners have been increasingly successful, such as in small smelting plants, because they have been found to be flexible in performing and produce a limited amount of fumes.
In the known devices, the rotary furnace is disposed as a single station in the vicinity of the chimney, to which it is connected by means of a movable connection enabling to tilt the furnace during the loading step. Once the loading has been carried out, the oxy-combustible burner is operated to carry out the smelting step, which for a load of metal to be smelted of the order of 3 tons, lasts about 1 hour and 30 minutes, with a first step, of about one hour, where the burner burns a stoichiometric mixture of fuel and oxygen, then, in order to limit the oxidation of the metal during the smelting operation, a second step, of a duration of about 30 minutes, is provided with a mixture depleted in oxygen. During this second step, the fumes which are withdrawn through the chimney contain, in addition to carbon dioxide and water vapor, carbon moxoxide and hydrogen, which, combined with the demand of draft air in the chimney, frequently induces the formation of flames in the chimney which could severely damage the latter and prevents an efficient cleaning of the fumes.